Refrigerant Replacement

A good HOUR on the vacuum pump is best...

 

I would not do this yourself if you are an ac novice. Pulling a strong vacuum and getting the moisture out takes time, tools and expertise. Oil is throughout the system. Leak testing. Triple evacuation process if necessary. Possibly some heating of the compressor. Followed by breaking the vacuum with refrigerant without introducing air. For $200 I would let them do it. The catch 22 is a diy job may work initially but fail later when the rest of us are at 300,000 with no ac service ever.

 

Inch pounds is 1/12th of ft pounds. You should use an inlbs torque wrench or just make it snug.

 

87 inch/pounds is 87/12 (7.25) foot/pounds.

 

A ftlb torque wrench capable of wheel lugs will be low range limited around 15-20 ftlbs depending on the manufacturer. Use the right tool.

By the way, circuit breaker lug torque is also spec'd as inch pounds. Typically 20-35 inch pounds for 12-14 awg. I have inspected a few electrician's work and found gross overtorque of breakers as well. Some manufactures will list it as pound inches in an attempt to wake up the installer.



So, inch pounds and foot pounds has got it? Not always. There are some devices specified as inch ounces. Somewhat rare.

 

Experienced technicians know, that with M6x1.0 bolts and nuts (10mm hex), a good rule to follow is to never tighten the fastener more than a 1/4 or 90 degrees turn after full run down contact even when using a torque wrench. That equates to 87 inch pounds.

 

Conversion issues aside, the value is hopefully in attached.

 

Another caveat; Never use a wrench with a lever arm longer than one on a 1/4 inch drive ratchet to tighten an M6 (10mm hex head) bolt or nut.

 

Or choke up* on the wrench; hold it closer to the fulcrum. Or one-hand it.

(* baseball term: gripping the bat further up)

 

76 ft/lb, yes.

Rest of the world uses 80 ft/lb, for cars of this ilk.

 

In high school auto shop in that big, 250 350 page textbook.
There is a chart that your tots by the instructor that shows you the diameter of the bolt, the hardness of the bolt, the size of a head and then there was a cross reference chart to show you exactly what the torque should be depending on the material it was made out of.
And that would always bring you to the torque range of which any manufacture, with specify in the repair manual.

It was the same thing. My father showed me as a child before high school.

And then later, when you go back into trade school or automotive engineering, this gets ran by you again as a refresher

But I keep hearing many old timer, saying schooling is not necessary. You could learn on the job by breaking things.. I’ve heard schools don’t teach you anything, many times

interesting

 

Like anything else, there are old timers with different levels of skills.

There are those with 25 years of experience and those with the same one year of the same experience twenty five times repeated.

 

It doesn't take much experience, before one realizes that he or she is applying too much force to a bolt or nut that doesn't move like others of the same size in the set. Too much force equals breakage.